Cannot configure 7Mode connection to Harvest

I am using the latest (1.2.2) version of Harvest. It is gathering metrics fine from a number of CDOT clusters. I am configuring it to connect to a 7-Mode cluster. I have followied the install guide and created a new user on the 7Mode controller as follows:

Going into the Harvest menu and configuring a connection, the authentication fails. The 'login-http-admin' privilege is defined for my user, so I cannot tell why the connection setup is failing.

Just as a test, I also tried to setup the Harvest connection as the root user, and that also failed. So I do not think the problem is related to the username, but maybe to a security option which is set on the controller?